What will be the iPhone 5’s must-have accessory?

Apple has gotten really good at driving up how much its customers spend with accessories.

The best recent example is the iPad 2 “smart” cover, which was designed in tandem with the tablet. It’s stylish, functional, and an Apple exclusive. And it’s one of the reasons that Apple’s June quarter revenue-per-iPad (including accessories) was up $50 from the March quarter.

For last year’s iPhone 4, Apple seemed set with its multi-colored “bumper” cases. But the Antennagate fiasco forced Apple to give away plain black bumpers (and third-party cases) for free, delaying the launch of paid, pricey, colorful bumpers.

So what does it have in store for the next iPhone? (Which it’s set to unveil next Tuesday.) More bumpers? New cases? Different earphones? Something completely different?

Also: What should Apple do with the iPod?